IMEC puts wave processing onto ECG patch
Researchers at IMEC’s Holst Centre have added the ability for their wireless ECG patch to perform wave analysis locally. The patch is intended to monitor the heart under daily-life conditions.
The electronics in the patch are carried on a flexible polyimide substrate and then embedded in a textile. This enables flexibility in one dimension and stretchability in the other. The patch uses an ASIC to extract the bio-potential signals produced by ECG measurements, a commercial microcontroller and a 2.4GHz radio link.
The patch can continuously monitor the patient’s heart at a sample rate of up to 1kHz. It sends the results directly to the receiver, or it can analyse the signals locally before sending them. Local analysis reduces the use of the radio, improving the autonomy of the patch. The current autonomy with local delineation is ten days of continuous monitoring.
The wave-processing algorithm detects the important electrical waves produced by the heart. The delineator is able to identify P, Q, R, S, and T wave peaks and boundaries. As the intervals and amplitudes of these waves contain most of the useful information of the ECG, this delineation should provide quick and useful information to the healthcare provider.
The delineator on the ECG patch was tested on the recordings in the MIT QT database. IMEC said its ECG patch achieves a 99.93 per cent sensitivity and a 98.28 per cent positive predictivity for QRS detection on 86,994 beats. For delineation over 3,623 beats, it reaches a 99.83 per cent sensitivity and a 95.08 per cent positive predictivity.
Bert Gyselinckx, Human++ program director, said: “We see that the Human++ technical progress is reflected in a growing industrial interest. Our physiological monitoring systems are based on ultra-low power wireless communication and start to make use of innovative energy harvesting technology. They are finding applications in sleep staging analysis, cardiac arrhythmia detection and epilepsy monitoring. The growing interest from industry worldwide is proven by new partnerships.”
National Semiconductor recently joined the Human++ program. Other Holst Centre partners include Alcatel-Lucent, ASML, Bekaert, NXP, Philips, Target Compiler Technologies and Texas Instruments.